title: Vitamin K-dependent carboxylation. Evidence that at least two microsomal dehydrogenases reduce vitamin K1 to support carboxylation.
abstract: It has been shown that NAD(P)H dehydrogenase (EC 1.6.99.2) reduces vitamin K1 and can support the [vitamin K1 + NADH]-dependent carboxylation reaction in rat liver microsomes (Wallin, R., Gebhardt, O., and Prydz, H. (1978) Biochem. J. 169, 95-101). Antibodies were raised in rabbits against the purified enzyme from liver cytosol and used to study the importance of NAD(P)H dehydrogenase in the vitamin K-dependent carboxylation reaction. The antibodies neutralized the warfarin-sensitive NAD(P)H dehydrogenase activity in Triton X-100-solubilized microsomes; however, they neutralized only 45% of the total [vitamin K1 + NADH]-dependent carboxylation activity. Chromatography on protein A-sepharose showed that the remaining carboxylase activity was not the result of soluble antigen-antibody complexes. The data presented support the conclusion that the microsomal preparation also contains a non-warfarin-sensitive dehydrogenase(s) that, in addition to NAD(P)H dehydrogenase, can reduce vitamin K1 to support the carboxylation reaction.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D016660:NAD(P)H Dehydrogenase (Quinone); D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism*; D010084:Oxidation-Reduction; D011808:Quinone Reductases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014812:Vitamin K / Q000378:metabolism / Q000494:pharmacology*; D014859:Warfarin / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D007074:Immunoglobulin G; D014812:Vitamin K; D014859:Warfarin; D009247:NADH, NADPH Oxidoreductases; D016660:NAD(P)H Dehydrogenase (Quinone); D011808:Quinone Reductases